Capturing Nonlinear Vibratory Roller Compactor Behavior through Lumped Parameter Modeling

Abstract

Continuous monitoring of soil properties using an instrumented roller compactor requires models that can capture the essential features observed during drum/soil vibration. This paper presents the results of lumped parameter modeling of the drum/soil system together with data from complex nonlinear behavior observed experimentally during operation on sandy soil. Model parameters and response were developed using experimental data collected over a wide range of operating frequencies. Three and four-degree-of-freedom ͑DOF͒ models with linear and nonlinear soil elements were investigated. The results showed that a 3DOF model incorporating the soil, drum, and frame of the roller was successful in capturing behavior during coupled drum/soil vibration and during decoupling ͑i.e., loss of contact between drum and soil͒. Modeling the drum/soil decoupling accounted for most of the experimentally observed nonlinearity. The addition of nonlinear soil stiffness due to the curved drum effect and due to strain hardening soil behavior accounted for additional nonlinearity observed experimentally. Experimentally observed drum rocking during coupled drum/soil vibration was successfully modeled with a 4DOF drum-frame model. The analysis also revealed that commonly observed heterogeneous soil conditions give rise to a transient response that can have a significant influence on vibration behavior.

Analytical modeling of the stick-slip motion of an oscillation drum

“…The dynamic (alternating) tangential (shear) forces, imposed through friction in the contact area between drum and surface of the compacted medium, induce mainly shear waves in the subsurface, and compaction is achieved by "massaging" the material [8], also referred to as shear force compaction [22]. Unlike in a vibrating drum, which may bounce during compaction [2,23], the compaction forces strain continuously the subsoil because oscillation drum and soil remain in permanent contact. An oscillation drum performs either a pure rolling motion or a stick-slip motion.…”

“…At the bottom of the settlement trough (point A in Fig. 2), in a common approach the effect of the elastic continuous halfspace (subsoil) is captured simplified through two discrete Kelvin-Voigt bodies ( [2,23,25]), one arranged in vertical direction (subscript sv) and one in horizontal (subscript sh) direction. The settlement trough exhibits a translational motion in both horizontal and vertical directions; its rotation is, however, constrained.…”

“…The literature on mechanical modeling of roller-compactors for numerical response simulation is quite scarce. Basically, it can be distinguished between finite element (FE) models (e.g., [3,9]) and lumped parameter models (e.g., [2,14,23]) of the dynamic interacting roller-subsurface system. The focus of most FE models is to predict the subsurface compaction and, depending on the degree of sophistication, allow only selective insight into the system response, like experimental studies.…”

Silage production technology using grass thickening vibratory method

“…According to the classic vibration theory, it is possible to scrutinise the system of plant thickening by vibratory method as a concentrated mass on a spring when it's other end is steadily set [13]. One of the most common dynamic inputs is excitation by a centrifugal force of nonweighted masses [11,12]. By requiring the excitation force to be oriented in a certain direction, an appropriate vibrator construction is needed.…”

“…But for practical issues these models are very complicated. This compaction task is simplified if a model of the vibrating system is constructed using a single degree of freedom according to the classical theory of mechanical oscillations [11,12].…”